FIG. 8 shows one described in PTL 1 as a heretofore known example of this kind of rotational operation type switch.
A rotational operation type switch 50 shown in FIG. 8 includes a rotary knob 52 which is rotatably supported on the upper end of a frame 51. The frame 51 is fastened and fixed to the mounting panel of an control board (not shown) by a fastening nut 53. A rotating cylinder 55 linked to the rotary knob 52 is rotatably housed in the frame 51, and a cylindrical cam 56 is linked to the lower end of the rotating cylinder 55. A contact unit 57 is linked to the lower end of the frame 51. The leading end of a push bar 58 which operates and switches the contact of the contact unit 57 abuts against the cam surface of the cylindrical cam 56.
The rotary knob 52 is structured so as to be rotationally operable by inserting an operation key 60 therein in order to prevent an unintended rotational operation.
When operating the rotational operation type switch 50 structured in this way, the operation key 60 is inserted into the rotary knob 52, and the key 60 is rotationally operated in a right or left direction. The rotary knob 52 rotates with the rotation of the key 60, in conjunction with which the rotating cylinder 55 and the cylindrical cam 56 rotate. The push bar 58 is moved up and down in response to a change in position of the cam surface by the rotation of the cylindrical cam 56, and a contact mechanism 59 of the contact unit 57 is driven by the lower end of the push bar 58, thus switching (on and off) the contact.
This kind of heretofore known rotational operation type switch is formed such that the contact of the contact unit 57 can be switched by rotationally operating the rotary knob 52, but is structured by the contact unit and an operation mechanism which operates the contact unit being completely unitized and linked to each other in an axial direction. Therefore, there is the problem of an inevitable increase in the depth dimension of the switch from the operation surface of the switch. Also, when structuring the switch as a rotary selector switch, it is necessary to annex a number of contact mechanisms corresponding to the number of contact mechanisms to be selected, meaning that there is also the problem of an increase in the price of the switch as well as an increase in the overall size of the switch.